U.S. patent application number 11/095182 was filed with the patent office on 2006-10-12 for treatment for ultrasonic welding.
This patent application is currently assigned to Xerox Corporation. Invention is credited to John Josephy III Darcy, Scott Griffin, David W. Martin, Michael Stephen Roetker, Felix J. Santana.
Application Number | 20060225842 11/095182 |
Document ID | / |
Family ID | 37082048 |
Filed Date | 2006-10-12 |
United States Patent
Application |
20060225842 |
Kind Code |
A1 |
Darcy; John Josephy III ; et
al. |
October 12, 2006 |
Treatment for ultrasonic welding
Abstract
A metal welding horn having tripartite ceramic coating on its
welding horn tip.
Inventors: |
Darcy; John Josephy III;
(Webster, NY) ; Roetker; Michael Stephen;
(Webster, NY) ; Martin; David W.; (Walworth,
NY) ; Santana; Felix J.; (San German, PR) ;
Griffin; Scott; (Fairport, NY) |
Correspondence
Address: |
PILLSBURY WINTHROP SHAW PITTMAN, LLP
P.O. BOX 10500
MCLEAN
VA
22102
US
|
Assignee: |
Xerox Corporation
|
Family ID: |
37082048 |
Appl. No.: |
11/095182 |
Filed: |
March 31, 2005 |
Current U.S.
Class: |
156/580.1 ;
156/580.2; 156/73.1 |
Current CPC
Class: |
B29C 66/71 20130101;
B29C 66/71 20130101; B29K 2025/08 20130101; B29K 2827/18 20130101;
B29K 2883/00 20130101; B29K 2909/02 20130101; B29K 2905/12
20130101; B29C 66/71 20130101; B29C 66/9517 20130101; B29C 66/81427
20130101; B29C 66/8122 20130101; B29C 66/8122 20130101; B29C
66/8122 20130101; B29C 66/8145 20130101; B29K 2055/02 20130101;
B29K 2905/08 20130101; B29K 2905/10 20130101; B29K 2909/02
20130101; B29L 2029/00 20130101; B29C 66/8122 20130101; B29C
66/81264 20130101; B29C 66/9513 20130101; B29C 65/7847 20130101;
B29C 66/8122 20130101; B29C 66/73921 20130101; B29C 66/8122
20130101; B29C 66/8122 20130101; B29C 65/08 20130101; B29C 66/81241
20130101; B29K 2995/007 20130101; B29K 2705/00 20130101 |
Class at
Publication: |
156/580.1 ;
156/073.1; 156/580.2 |
International
Class: |
B32B 37/00 20060101
B32B037/00 |
Claims
1. An ultrasonic welding horn comprising: a metal substrate having
a bottom portion and a tip portion operatively configured to
transmit ultrasonic energy; wherein the tip portion is coated with
a tripartite oxide-ceramic coating having a total thickness of
about 10 microns to about 50 microns and comprising: a metal oxide
layer in contact with the metal tip portion; a dense ceramic
coating layer in contact with said metal oxide layer, the dense
ceramic coating layer having a hardness of about 400 to about 2000
HV; and a lenticular porous ceramic layer in contact with said
dense ceramic layer.
2. An ultrasonic welding horn in accordance with claim 1, wherein
the metal of the metal substrate is aluminum, titanium, magnesium
or an alloy thereof, or a combination thereof.
3. An ultrasonic welding horn in accordance with claim 1, wherein
the metal oxide layer comprises a thin layer providing molecular
bonding between said metal and said dense ceramic layer.
4. An ultrasonic welding horn in accordance with claim 2, wherein
the dense ceramic coating layer comprises a densely fused ceramic
structure.
5. An ultrasonic welding horn in accordance with claim 2, wherein
the lenticular porous ceramic coating layer has substantially
uniformly distributed pores.
6. An ultrasonic welding horn in accordance with claim 5, wherein
the lenticular porous ceramic coating layer is impregnated with a
material selected from the group consisting of
polytetrafluoroethylene, silicon, copper, iron, zinc, magnesium,
zirconium, and titanium.
7. An ultrasonic welding horn in accordance with claim 1, wherein
the lenticular porous ceramic coating layer contains pigment.
8. An ultrasonic welding horn in accordance with claim 1, wherein
the tripartite oxide-ceramic coating is created by pulsed-voltages
of positive and negative polarity.
9.-10. (canceled)
11. An ultrasonic welding horn in accordance with claim 1, wherein
the lenticular porous ceramic layer has a friction coefficient of
less than 0.15 against steel.
12. An ultrasonic welding horn in accordance with claim 1, wherein
the tripartite oxide-ceramic coating comprises spinel and/or
corundum.
13. A resonator comprising: a top portion; and an open bottom
portion coated with a tripartite oxide-ceramic coating having a
total thickness of about 10 microns to about 50 microns and
comprising: a light metal oxide coating layer; a dense ceramic
coating layer in contact with said metal oxide coating layer, the
dense ceramic coating layer having a hardness of about 400 to about
2000 HV; and a lenticular porous ceramic layer in contact with the
dense ceramic layer.
14. A resonator in accordance with claim 13, wherein further
comprising a piezoelectric material between said top portion and
said bottom portion.
15. A resonator in accordance with claim 13, wherein the dense
ceramic coating layer comprises a spinel and/or corundum.
16. A resonator in accordance with claim 15, wherein the lenticular
porous ceramic coating layer is modified with a coating
substance.
17. A resonator in accordance with claim 16, wherein the coating
substance comprises PFTE, paint/pigment, or metal.
18. A resonator in accordance with claim 17, wherein the metal
comprises iron, copper, zinc, titanium, zirconium, or
magnesium.
19. A resonator in accordance with claim 13, wherein the resonator
comprises a substrate material of aluminum, titanium, or
magnesium.
20. (canceled)
Description
BACKGROUND
[0001] All references cited in this specification, and their
references, are incorporated by reference herein in their entirety
where appropriate for teachings of additional or alternative
details, features, and/or technical background.
[0002] Flexible imaging belts include electrophotographic imaging
belts, ionographic/electrographic imaging belts, and intermediate
image transfer belts for transferring toner images used in an
electrophotographic or an electrographic imaging system. Such
flexible imaging belts may include photoreceptor layers containing
a substrate, an electrically conductive layer, an optional hole
blocking layer, an adhesive layer, a charge generating layer, and a
charge transport layer and, in some embodiments, an anti-curl
backing layer. A layered photoreceptor having separate charge
generating (i.e. photogenerating) and charge transport layers is
described in U.S. Pat. No. 4,265,990.
[0003] Flexible imaging belts may be fabricated from a cut sheet of
an imaging member web. The sheets which may comprise square,
rectangular or parallelogram shapes can be configured into a belt
by joining the overlapping opposite marginal ends of the sheet to
form a seam. The joining technology may involve welding (including
ultrasonic welding), gluing, taping, or pressure heat fusing.
[0004] Ultrasonic welding may be the method chosen for joining a
flexible imaging member because it is rapid, clean and solvent-free
and low cost, as well as because it produces a thin and narrow
seam. In addition, ultrasonic welding may be preferred because the
mechanical high frequency pounding of the welding horn causes
generation of heat at the contiguous overlapping end marginal
regions of the flexible imaging sheet loop to maximize melting of
one or more layers therein to form a strong and precisely defined
seam joint.
[0005] Ultrasonic welding is a process that uses high frequency
mechanical vibrations above the audible range. The vibrations are
produced at the tip of a welding sonotrode or horn. The vibratory
force emanating from such a horn device can be generated at high
enough frequencies to soften or melt thermoplastic material
components intended to be joined together. For example, such
frequencies can be effective at 20, 30 or 40 kHz. One of the main
advantages of ultrasonic welding may be found in the very short
welding steps that enhance its usefulness even in mass production.
Weld times may last less than a second. Thus, the process has been
utilized in many industries and applications.
[0006] Ultrasonic welding can be accomplished at various distances
from the horn ranging from only a fraction of a millimeter up to
several centimeters. For distant welding the polymer must transmit
the energy efficiently, i.e. not be too flexible or have too high a
loss modulus. A copolymer of acrylonitrile, butadiene, and styrene
(ABS) and high impact polystyrene is among the easiest polymers to
weld ultrasonically. Ultrasonic welding will usually join amorphous
thermoplastics more readily than semicrystalline ones. However, the
advent of more powerful machines has blurred this distinction, and
semicrystalline polymers are now welded routinely.
[0007] The ultrasonic welding process may entail holding down the
overlapped ends of a flexible imaging member sheet with vacuum
against a flat anvil surface and guiding the tip end of an
ultrasonic vibrating horn transversely across the entire width of
the sheet, over and along the overlapped ends, to form a welded
seam. The ultrasonic vibration frequency applied for joining the
photoreceptor belt/loop ends is kept so high that a frictional heat
results upon contact with material to be joined. The heat causes
softening or melting of contact portion which results in fusing the
joined belt end pieces without any horn burn blemishes in the form
of undesirable raised, rough and brittle welds.
[0008] Ultrasonic welding is probably the most commonly used
thermoplastic welding process because it is very fast (fractions of
a second to a few seconds) and usually produces welds that are
relatively free of flash. In addition, ultrasonic welding can be
automated and thus is particularly suitable for high volume
production.
[0009] Rapid development of the ultrasonic welding machine has
occurred in the last ten years. Basic functions, such as weld
energy, collapse, trigger force, and pressure are now
microprocessor controlled. In addition, real time feedback and
control of welding conditions is being offered, along with the
ability to vary weld force and amplitude during the weld
cycles.
[0010] Welding by ultrasonic devices requires a tool design
suitable for the particular task at hand. The mechanical
characteristics of the substrate will determine the selection of
the welding machine. An ultrasonic welding device typically
includes four main components, a power supply, a converter, an
amplitude controlling device or booster, and an acoustic tool which
is called the horn or sonotrode. The electricity is changed by the
power supply, for example, from 50-60 Hz into a high frequency such
as 20, 30, or 40 kHz and then supplied to a converter. The
converter may comprise discs of piezoelectric crystals wedged
between two metal sections and kept tightly compressed to respond
to even the slightest pressure change. The converter serves to
change the electrical energy into mechanical vibration energy at
high ultrasonic frequencies. The vibratory energy is transmitted
through the booster. The booster increases the amplitude of the
sound wave to the horn.
[0011] The horn is an acoustical tool delivering ultrasonic
vibratory energy directly to the substrate portions being
assembled. In addition, the horn is used to apply welding pressure.
The vibrations are transmitted from the horn to the joint area or
seam, where the resultant friction causes the surface of the
substrate material to soften or melt, and subsequently fuse
together. Ultrasonic welding may be used to join flexible image
photoreceptor loops as well as intermediate transfer belts and
weldable polymer substrate belts.
[0012] Flexible image loops photoreceptors and imaging belts may be
joined together at opposite ends to form a continuous loop by
ultrasonic acoustic welding horns which transfer vibration energy
to the bondable substrates. The ultrasonic welding process involves
flexing of the slender projection or tip portion of a metallic
welding horn member by oscillating at rates of 10,000 to 70,000
times per second (kHz). The oscillation causes the horn tip portion
to move across the flexible belt joint area to create a weld or
seam. The horn member can be held at a distance from the joint
surface suitable for effective mechanical energy delivery to the
joint area which rests on its opposite side on, for example, on an
anvil ensuring that most of the energy is spent in the weld zone of
the joint area. The overlapping ends of the flexible thermoplastic
belt sheet consequently melt forming a weld or seam. Frictional
heating can also occur to some extent because transmission of the
energy through the plastic parts is very complex.
[0013] An oscillating force of an ultrasonic horn is generated when
alternating electrical power (at frequency) is applied to a train
of tuned components that are sized to form a resonant system. The
first component converts the electrical power (i.e. voltage) to
oscillations. This occurs when the power is applied to a sandwich
of piezoelectric or magnetostrictive materials and metal blocks.
These oscillations are amplified (or de-amplified) by a booster and
the booster is connected to the horn. The horn can either amplify
or de-amplify the oscillations, depending on the needs of the
application. While the frequency of oscillations vary between 10
and 70 kHz, the most common frequencies are in the range from 20 to
40 kHz. Oscillation amplitudes range from 20 to 80 microns.
[0014] The piezoceramic material may include one or more of barium
titanate (BaTiO.sub.3), lead zirconate titanate (PZT), or lead
titanate (PbTiO.sub.3). Most preferably, the piezoceramic is PZT.
The polymer of the composite may include any suitable binder
polymer, and may or may not itself be piezoelectric. Piezoelectric
polymers include polyvinylidene fluoride (PVDF), and copolymers of
vinylidene fluoride and trifluoroethylene (PVDF/TrFe) or vinylidene
fluoride and tetrafluoroethylene (PVDF/TeFe). Other binder polymers
may include, for example, epoxies, silicone resins, cyanoacrylates,
etc., without restriction. A preferred polymer is an epoxy in that
it can also act to strongly adhere the piezoelectric composite to
the platform section of the horn member.
[0015] The 1-3 configuration nomenclature that identifies the
configuration of the piezoelectric composite transducer is known in
the art and refers to the two-phase piezoelectric behavior of the
material, the first number referencing the physical connectivity of
the active phase (z direction) and the second number referencing
the physical connectivity of the passive phase (y direction). The
1-3 composite configurations have been found to be most
advantageous in achieving consistently uniform tip vibration
amplitude. For example, the piezoelectric composite may be bonded
with an adhesive layer to horn. A vast array of adhesives such as
transfer adhesives, epoxies, cyanoacrylates, or an epoxy/conductive
mesh (e.g., metal screen) layer may be used to bond the horn and
piezoelectric element together.
[0016] Ultrasonic welding may lead to a welding defect known as
"Horn Burn." "Horn Burn" results in a raised, rough, and brittle
welds, which are all unwanted traits. "Horn Burn" has been
associated with the ability of the horn to transfer heat out of the
seamed area. While numerous materials have been used in the
fabrication of horns, aluminum has shown itself to be an effective
head dissipating material. The main disadvantage of aluminum is its
inherent softness. The configured ultrasonic horn tip wears away
after several weld cycles. The constant wear due to the welding
friction results in equipment downtime for converting, the cost of
ultrasonic horn tooling, and defective belts. Various ceramic
plating methods have been tried in the past to improve the wear
resistance of ultrasonic horns, but have shown a tendency to
delaminate. In respect of ceramic plating, it has been found that
the ultrasonic energy's elongation of the welding horn may break
the plating bond after only a few cycles.
SUMMARY
[0017] Aspects disclosed include
[0018] an ultrasonic welding horn comprising a metal form having a
bottom portion and a tip portion operatively configured to transmit
ultrasonic energy, said tip portion coated with a tripartite
structure comprising a metal oxide layer in contact with the tip
portion, a dense ceramic layer in contact with said metal oxide
layer, and a lenticular porous ceramic layer, wherein the metal is
aluminum, titanium, magnesium or an alloy thereof, or a combination
thereof, the metal oxide layer comprises a thin layer providing a
molecular bonding between said metal and said dense ceramic layer,
the dense ceramic coating layer comprises a densely fused ceramic
structure, and the lenticular porous coating layer comprises
substantially uniformly distributed pores.
[0019] A resonator having a top portion and an open bottom portion
coated with a tripartite ceramic surface comprising a metal oxide
layer, a dense ceramic layer in contact with said metal oxide layer
and a lenticular porous layer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] In the detailed description reference is made to the
illustrative figures listed below.
[0021] FIG. 1 illustrates an oblique view of an ultrasonic horn
(prior art);
[0022] FIG. 2 illustrates a cross-sectional view of an ultrasonic
horn assembly; and
[0023] FIG. 3 illustrates a multi-layered protective plating on an
ultrasonic horn tip surface.
DETAILED DESCRIPTION
[0024] In the embodiments there is illustrated a hardened light
metal ultrasonic welding horn surface protected by a corrosion,
heat and delamination resistant ceramic layer.
[0025] In embodiments there is also illustrated a welding horn
coating comprising a multilayer comprising a metal oxide layer in
contact with the horn, a dense ceramic layer in contact with the
metal oxide layer, and a lenticular porous ceramic layer in contact
with the dense ceramic layer.
[0026] In one embodiment, there is illustrated a special hardening
process of light alloy horns that significantly enhances the
quality and quantity of acoustic welding fabrication of
photoreceptor belts. Such process coats the alloy surface of a
metallic horn with a complex ceramics coating to lend improved
hardness and wear characteristics, and provide substantially
uniform coating. The coating may be applied to only a portion of
the ultrasonic welding horn such as the tip to afford sufficient
protection against high mechanical stress from vibration, friction
and heat, and prevention of "Horn Burn."
[0027] In one embodiment of the invention, there is disclosed an
ultrasonic horn comprising elemental, or an alloy of, aluminum,
magnesium, and/or titanium, and/or mixtures thereof. Such horn may
be coated with a coating comprising, in order from the layer
farthest from the metal horn to the metal horn itself, a porous
ceramic outside layer, a dense main layer of fused ceramics with
the fused ceramic closest to the substrate being more dense, and a
thinner metal oxide layer providing a molecular bond between the
metal or the ceramic coating. The top outside porous layer may
further comprise materials such as polytetrafluoroethylene, paint
or additive materials such as iron, copper, magnesium, titanium,
zirconium, and zinc. The thin intermediate metal oxide layer
provides a strong molecular bond between the metal substrate and
the dense ceramic matrix and reduces the likelihood of cracking or
chipping. The dense ceramic layer provides hardness and wear
resistance. The outer porous layer may comprise a lenticular
surface with substantially evenly distributed fine pores. Such
pores allow for impregnation of materials, such as
polytetrafluoroethylene (PTFE), paint, or additive metals including
iron, copper, magnesium, titanium, zirconium, and zinc, which leads
to better wear resistance and better scratch resistance. The porous
outside layer of a PETRALITE.TM. surface may have a friction
coefficient of less than 0.15 against steel, and a hardness range
of the dense main layer of about 400 to about 2000 HV, or about 400
HV to about 1000 HV, about 400 to about 500 HV (R.sub.c 35 to 55).
A coating of the present disclosure may comprise a tripartite
pulsed-voltage ceramic coating such as PETRALITE.TM.. A tripartite
pulsed-voltage ceramic coating may be formed using a KERONITE.TM.
process, or a KERONITE.TM.-like process, such as disclosed for
example in U.S. Pat. No. 5,385,662, and U.S. Pat. No. 5,487,825. As
described in such references, a plasma discharge caused by
electrical pulses, preferably of both positive and negative
polarities, in pulsed fashion, is caused to interface with the
surface of the metal/metal alloy while it is in contact with a low
alkaline electrolyte bath concentrate. The bipolar pulsed plasma
discharged causes oxidation of the surface (via "plasma
electrolytic oxidation" or "PEO"), elementary co-deposition, and
the fusion of a metal oxide layer formed on the metal/metal alloy
to a deposited ceramic layer. A KERONITE.TM. process may eventuate
in a uniform thickness tripartite coating of about 10 microns to
about 60 microns. The alkaline electrolyte bath, useful in a
KERONITE.TM.-like process, may for example comprise components
useful in the anodization process such as the chloride-free
electrolytic bath of Example 1 of U.S. Pat. No. 5,487,825. The bath
need not contain chrome or ammonia.
[0028] When magnesium materials are the metal/metal alloy substrate
upon which a tripartite pulsed-voltage ceramic coating is placed, a
layer of spinel (MgAL.sub.2O.sub.4) may predominate in the dense
ceramic layer. When aluminum materials are used as the substrate,
corundum may predominate in the dense ceramic layer.
[0029] By "ceramic" it is meant to include a chemical inorganic,
except metals and alloys, that are manufactured by the action of
heat. Generally, ceramics comprise both cationic and anionic
species and possess ionic bonding.
[0030] The high frictional and heat energy of an ultrasonic welding
routine tends to wear away the smoothly plated or polished tip of
the horn during the welding operation. The resulting downtime of
the welding process for repair and converting equipment is
expensive in both time and material. Various ceramic plating
methods have been tried but have failed by delaminating the
exogenous plating layers. A tripartite pulsed-voltage ceramic
coating applied to the horn tip portion protects the tip surface,
and overcomes the fragility of welding horns made from light metal
alloys.
[0031] The hardness of the tripartite pulsed-voltage ceramic
coating may range from about 400 to about 2000 HV, depending on the
type of alloy and the depth of the applied coating. With respect to
PETRALITE.TM., high corrosion resistance is observed in that the
treated alloys remain unaffected in corrosive salt baths for over
2000 hours and withstand continuous exposures to temperatures as
high as 500.degree. C., and for brief periods, thermal shocks of up
to 2000.degree. C., without apparent damage. Suitable alloys for
coating include magnesium and titanium alloys which may contain
admixtures of copper, magnesium, silicon, zinc, and/or iron.
[0032] Contrary to conventional plating methods whereby hard
substances are added to a substrate surface, the hardening
treatment of, for example, the aluminum-based alloy substrate by
the pulsed-voltage ceramic coating technique involves a reaction
directly transforming the substrate surface creating atomic bonds
between the metallic substrate and the metal oxide-ceramic coating.
The method may achieve a uniform coat of controlled thickness
regardless of shape of the treated substrate.
[0033] Additional layers may be bonded to the porous outer ceramic
surface. Depending on need, the coating thickness may be adjusted
from a thin anticorrosion layer to a thick thermal resistant layer.
The specific coating layer is selected at a suitable thickness
providing the best wear resistance while avoiding a thickness that
may dampen the effective working vibration.
[0034] The treated alloy substrate forms a complex, fused ceramic
plating microstructure exhibiting hard crystalline phases which are
distributed in a matrix of softer phases of oxide. The embodiment
of the in situ modification of alloy surfaces is achieved by a
reaction that converts the substrate alloy, such as aluminum, into
a bonded oxidized alloy layer which thickness increases with time
of reaction. This protective structural configuration gives the
surface of the horn tip portion alloy, combined properties of
considerable hardness and wear resistance, and resistance against
failure from shock and vibration. The combination of high
dielectric strength and heat resistance of treated alloy surface
serves to make the ultrasonic operation of such a resonating
welding horn durable.
[0035] The tripartite voltage pulsed ceramic coated horn may be
used in various arrangements or systems of ultrasonic welding of
photoreceptor belts. One method forms a flexible photoreceptor belt
by joining a first and second end into a flexible member loop
overlapping the first end and the second end in an overlap region
for a selected distance. The process provides a photosensitive
surface of the photoreceptor belt on the outside of the loop while
positioning a welding tool on an inside surface of the loop shape
of the flexible member opposite the overlap region and
ultrasonically welding the flexible member at one or more locations
along the overlap region producing a photoreceptor belt. Another
method of forming a flexible belt keeps the photosensitive surface
of the photoreceptor belt on the outside of the loop shape,
ultrasonically welding the flexible member from the inside of the
loop at one or more locations along the overlap region with an
ultrasonic horn directed to the work surface. A further method of
forming a flexible photoreceptor belt provides the photosensitive
surface on the outside of the loop while positioning the overlap
region of the member in a pressure contact with a work surface with
the photosensitive surface on the outside of the loop
ultrasonically welding the flexible member at one or more locations
along the overlap region using an ultrasonic horn; and then turning
the flexible member inside out after the welding step to move the
photosensitive surface originally formed on the inside of the loop
to the outside of the flexible belt loop. Another process of
producing a flexible photoreceptor belt provides a photosensitive
surface on the outside of the loop shape keeping the first end and
the second end of the flexible member on the photosensitive
surface, wherein the overlap region and the photosensitive surface
are in pressure contact with a work surface. With the
photosensitive surface of the flexible member on the outside of the
loop shape, the ultrasonic welding transverses along the overlap
region. Yet another method of forming a flexible photoreceptor belt
positions the overlap region of the flexible member at the joining
point in pressure contact with the work surface keeping the
selected surface on the outside of the loop shape, creating a
second dimensional area. As the welding tool is adjacent an inside
surface of the flexible member loop opposite the overlap region,
the welding tool has a third dimensional contact area for
ultrasonically welding the flexible member along the overlap region
forming a belt.
[0036] In addition to improving ultrasonic welding horns, the
tripartite voltage pulsed ceramic may also improve resonators used
to apply vibratory mechanical energy to a member. A resonator
includes an energy transmitting horn member combining a platform
portion and a horn portion which forms a contacting portion for
contacting a surface of the member. The design of a resonator may
include a piezoelectric material in association with the horn
member for driving the horn member to vibrate. The piezoelectric
material may be responsive to a voltage signal from a voltage
source, and may be composed of at least one piezoceramic material
and at least one of a polymer or air, at a 1-3 configuration.
[0037] FIG. 1 shows an oblique view illustrating a multi-horn
component 10 (prior art) where the horn tip assembly 20 is a
side-by-side combination of horn segments 1, 2, 3, 4, 5 and 6,
extending from a base 40 containing an optional piezoelectric layer
30 and an electric cable attachment receptacle 35. When horn 10 is
fully segmented, each horn segment tends to act as an individual
horn. When the horn is segmented though the tip, producing an
open-ended slot, each segment acts more or less individually in its
response. It will be understood that the exact number of segments
may vary from the six segments shown in the Figure.
[0038] FIG. 2 (prior art) depicts a cross-section of a stack
assembly 50 of an ultrasonic welding device wherein the horn
portion 55 is attached to a booster 60 which in turn is attached to
a transducer 65. The stack represents a tuned resonator wherein the
tuned welding stack 50 matches the frequency of the electrical
signal from the generator (cable 70) to within about 30 Hz. The tip
surface 58 is directed to the work surface 75 of a photoreceptor
belt joining portion 80.
[0039] FIG. 3 depicts a cross-section of an ultrasonic tip 100
covered with a tripartite pulsed-voltage protective ceramic surface
105 (PETRALITE.TM.) combining a thin molecular oxide bonding inner
layer 106, a structural stabilizer dense ceramic middle layer 107
and a porous ceramic outer layer 108.
[0040] While the invention has been particularly shown and
described with reference to particular embodiments, it will be
appreciated that variations of the above-disclosed and other
features and functions, or alternatives thereof, may be desirably
combined into many other different systems or applications; also
that various presently unforeseen or unanticipated alternatives,
modifications, variations or improvements therein may be
subsequently made by those skilled in the art which are also
intended to be encompassed by the following claims.
* * * * *